package com.github.surpassm.config.json.codec;

import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
import java.security.SecureRandom;

/**
 * @author mc
 * Create date 2019/4/15 10:42
 * Version 1.0
 * Description
 */
public class DesEncryptUtil {

	private final static String DES = "DES";

	/**
	 * Description 根据键值进行加密
	 * @param data 数据
	 * @param key  加密键byte数组
	 * @throws Exception      ss
	 * @return s
	 */
	public static String encrypt(String data, String key) throws Exception {
		byte[] bt = encrypt(data.getBytes(), key.getBytes());
		return new BASE64Encoder().encode(bt);
	}

	/**
	 * Description 根据键值进行解密
	 * @param data 数据
	 * @param key  加密键byte数组
	 * @throws Exception ss
	 * @return s
	 */
	public static String decrypt(String data, String key) throws
			Exception {
		if (data == null) {
			return null;
		}
		BASE64Decoder decoder = new BASE64Decoder();
		byte[] buf = decoder.decodeBuffer(data);
		byte[] bt = decrypt(buf,key.getBytes());
		return new String(bt);
	}

	/**
	 * Description 根据键值进行加密
	 * @param data 数据
	 * @param key  加密键byte数组
	 * @throws Exception ss
	 * @return s
	 */
	private static byte[] encrypt(byte[] data, byte[] key) throws Exception {
		// 生成一个可信任的随机数源
		SecureRandom sr = new SecureRandom();

		// 从原始密钥数据创建DESKeySpec对象
		DESKeySpec dks = new DESKeySpec(key);

		// 创建一个密钥工厂，然后用它把DESKeySpec转换成SecretKey对象
		SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
		SecretKey securekey = keyFactory.generateSecret(dks);

		// Cipher对象实际完成加密操作
		Cipher cipher = Cipher.getInstance(DES);

		// 用密钥初始化Cipher对象
		cipher.init(Cipher.ENCRYPT_MODE, securekey, sr);

		return cipher.doFinal(data);
	}


	/**
	 * Description 根据键值进行解密
	 * @param data 数据
	 * @param key  加密键byte数组
	 * @throws Exception ss
	 * @return s
	 */
	private static byte[] decrypt(byte[] data, byte[] key) throws Exception {
		// 生成一个可信任的随机数源
		SecureRandom sr = new SecureRandom();

		// 从原始密钥数据创建DESKeySpec对象
		DESKeySpec dks = new DESKeySpec(key);

		// 创建一个密钥工厂，然后用它把DESKeySpec转换成SecretKey对象
		SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
		SecretKey securekey = keyFactory.generateSecret(dks);

		// Cipher对象实际完成解密操作
		Cipher cipher = Cipher.getInstance(DES);

		// 用密钥初始化Cipher对象
		cipher.init(Cipher.DECRYPT_MODE, securekey, sr);

		return cipher.doFinal(data);
	}

}
